Link from Thumbnail to Post not working

You probably have more than one query in your page, let’s make sure we are working with this query:

<?php
    $carouselPosts = new WP_Query();
    $carouselPosts->query('showposts=3');
    // checking if there are posts to show
    if($carouselPosts->posts){ 
       foreach ($carouselPosts->posts as $carouselPost) { 
        echo '<a href="'. get_permalink($carouselPost->ID). '">';
        echo '<div class="recentpostthumbnail">';
          echo get_the_post_thumbnail($carouselPost->ID,array(70,70));
        echo '</div>';
        echo '</a>';
        $excerpt = get_the_excerpt();
        if($excerpt)
             echo '<div class="recentpostscontent">'. $excerpt .'</div>';
        echo '<div class="clearfix"></div>';
      }
    }